Electric fuse



April 10, 192.8. 1,665,528

H. T BUSSMANN ELECTRIC FUSE Filed March 20, 1922 //v Vf/VTOR Patented Apr. 10, 1928.

HENRY T. BUSSMANN, OF ST. LOUIS, MISSOURI.

ELECTRIC FUSE.

i Application filed March 20, 1922. Serial No. 545,221. I

My invention relates to electric fuses and.

more particularly to the renewable ferrule contact type.

Fuses of this type are usually made with metal end pieces to receive the end caps,

as attaching the caps directly onto' the fibre is objectionable for a great many reasons.

These metal end pieces are held to the fibre by being threaded thereon but no satisfactory method for preventing the turning or unscrewing of these pieces has heretofore been devised. It has been endeavored to prevent the turning of these end pieces by staking or punching a vportion of the metal end piece into the fibre. This has been unsatisfactory because with a little shrinkage of the fibre the fitting is again loose and therefore, this method is not at all dependable. In other cases a rivet has been used extending through the side walls of these metal end pieces and through the side walls of the tubing. This, however, is a very expensive method and on the smaller sizes of fuses is very difficult. The riveting interferes with and injures the threads and if the riveting is not perfectly done, flame and hot gases generated on the blowing ofthe fuse are permitted to escape, as this rivet hole opens directly into the tube. 1

It is the object of my invention to provid a means for fastening these metal end pieces in a manner that will give much more satisfactory results and at a much lesser cost than any of the methods heretofore used.

Fig. 1 is a view of a fuse showing a longitudinal section thereof.

Fig. 2 is an end view of the metal end pieces.

Fig. 3 is a detailed cross sectional view.

end piece attached to the casing by threads 6 as shown; 10 is a washer for seating the link 11; 7 shows capsattached to the metal end pieces. When a cap is removed from the metal end piece there is considerable strain tending to unscrew these end pieces from the fibre tube, particularly if there should be any sticking between the metal end piece and the cap as is sometimes caused by a deposit of metal from the blowing of the fuse. The method I use for preventing the turning of these metal end pieces is to insert a pin 8 through a hole in the end piece as shown at 9. This pin is driven intothe In the drawings, 4 is a casing; 5 is a metal fibrecasing and if necessary can be ground off at the top to provide a perfectly flush surface on the metal end piece The pin is preferably made one or two thousandths of an inch larger than the hole in the metal end piece so that it is securely fastened and there is nopossibility of it coming out. i It willbe seen from this that the cost of this fastening is very considerably less than where a rivet extending through the side wall of the casing is used, that it cannot interfere with the operation of the fuse and in every way presents a far more satisfactory method for accomplishing this Work than has ever before been evolved.

In describing the device shown in the drawings hereto attached and described in the specifications, I do not limit my invention to the use of such a holding means as the precise form, shape, construction or type of fuse shown nor to its use with the particnlar type of end piece shown, her to the particular kind of. a pin shown, as many alterations can be made without changing .the scope of my invention.

What I claim as my invention is 1. In a fuse, a fibre casing, a ring shaped member threaded to the casing, and a holding member to prevent rotational movement of the ring shaped member relative to the casing, said holding member extending longitudinally a relatively short distance into the casing, and being held against displacement by frictional engagement.

- 2. In a fuse, a fibre casing member, a ring shaped member threaded to the casing memher, and a holding element to prevent rotational movement of the ring shaped member relatively to the casing member, said holding element extending longitudinally a relatively short distance into the casing, and being in frictional engagement with one of said members.

3. In a fuse, a. fibre casing. a perforated ring shaped member threaded to the casing, and a holding member to prevent rotational movementof the ring shaped member relative to the casing, said holding member extending longitudinally a relatively short dis tance into the casing, and from said easing into the perforation in the ring-shaped member.

. 4. In a fuse, a fibre casing, a ring shaped member threaded to the casing, and a holding member to prevent rotational movement of the ring'shaped member relative" to. the

casing, said holding member extending loning member to prevent rotational movement of the ring shaped member-relative to the casing, said holding member being inserted in the outside end of thering shaped mem her and into the end of the casing and ex- Leeaeae tending a relatively short distance into the casing. a

6. ln a fuse, a fibre casing, a rim shaped member threaded to the casing, an a holding member to prevent rotational movement of the firing shaped member relative to the casing, said holding member being inserted in the outside end of the ring shaped member and into the end of the easing and extending a relatively short distance into the casing ind being held against displacement by frictional engagement.

HENRY 'll, BUSSMANN. 

